Intercontinental transport of tropospheric ozone: a study of its seasonal variability across the North Atlantic utilizing tropospheric ozone residuals and its relationship to the North Atlantic Oscillation

[摘要] Using the empirically-corrected tropospheric ozone residual (TOR) technique, whichutilizes coincident observations of total ozone from the Total Ozone MappingSpectrometer (TOMS) and stratospheric ozone profiles from the Solar BackscatteredUltraviolet (SBUV) instruments, the seasonal and regional distribution of troposphericozone across the North Atlantic from 1979-2000 is examined.Its relationship to theNorth Atlantic Oscillation (NAO) is also analyzed as a possible transport mechanismacross the North Atlantic.Monthly climatologies of tropospheric ozone for five differentregions across the North Atlantic exhibit strong seasonality.The correlation betweenthese monthly climatologies of the TOR and ozonesonde profiles at nearby sites in botheastern North America and western Europe are highly significant (R values of +0.98 and+0.96 respectively) and help to validate the use of satellite retrievals of troposphericozone.Distinct springtime interannual variability over North Atlantic Region 5 (easternNorth Atlantic-western Europe) is particularly evident and exhibits similar variability tothe positive phase of the NAO (R=+0.61, r=<0.01).Positive phases of the NAO areindicative of a stronger Bermuda-Azores high and a stronger Icelandic low and thusfaster more zonal flow across the North Atlantic from west to east.This flow regimeappears to be causing the transport of tropospheric ozone across the North Atlantic andonto Europe.The consequence of such transport is the impact on a downwind region'sability to meet their ozone attainment goals.This link between the positive phase of theNAO and increased tropospheric ozone over Region 5 could be an important tool forprediction of such pollution outbreaks.

[学科分类] 大气科学